>Every time a tech company produces something new MS have to muscle in on the market, despite having a) no prior experience, b) no aptitude, c) existing products that could use their attention.
Similar to what Google is also trying to achieve with Google+, especially with muscling in part? Although I don't like their approach, I can't blame them for going with it. There is a huge untapped market in the social segment and they were right to put a footing on it.
Android was bought in.